Cochrane in CORR ®: surgical versus conservative treatment for acute injuries of the lateral ligament complex of the ankle in adults (review).

Abstract

Importance of the Topic More than 650,000 ankle sprains present to emergency departments in the United States for treatment every year [14]. The vast majority of these sprains are injuries to the lateral ligament complex resulting from a forceful inversion of the ankle joint during physical activity [7]. The impact of a lateral ligament complex sprain is experienced through acute pain and swelling, several weeks of acute disability resulting in time lost from work or other activities, and in as many as 20% of patients, chronic instability of the ankle joint [1, 7]. Anatomically, lateral ligament sprains are almost always localized to the anterior talofibular ligament. The calcaneofibular ligament is also involved in 50% to 75% of sprains [2]. The third ligament of the lateral ligament complex - the posterior talofibular ligament - is rarely involved. In cases of chronic instability, anatomic reconstructive procedures (as originally described by Brostrom [4] and subsequently modified) frequently are used to correct a deficient lateral ligament complex and restore stability of the ankle joint [4]. It is plausible that primary repair of acute lateral ligament complex tears may facilitate ligament healing, shorten time off work and/or athletic activities, and reduce the incidence of chronic instability. However, surgical intervention also has inherent disadvantages, such as wound infection, iatrogenic nerve injury, and other postsurgical complications. The primary objective of this Cochrane Review is to determine whether surgical management is superior to conservative management of acute lateral ligament complex injuries [6]. Upon Closer Inspection The lack of a standardized patient-oriented outcome instrument provided unique challenges to this meta-analysis, and led to the need to independently evaluate 11 outcomes (four primary outcomes and seven secondary outcomes). A maximum of 12 of 20 trials reported data on a common outcome to allow for a meta-analysis. A validated, reliable, and universally accepted ankle outcome instrument would have facilitated a rigorous and informative meta-analysis of outcome data from all trials [5], but such an outcome instrument does not presently exist [3, 9]. A single trial published by Prins [10] in 1978 demonstrated several benefits of surgical management - results that differed substantially from other published trials, including several more-recent and better-designed efforts [8, 11-13] - and greatly influenced the pooled estimate for many outcomes. The pronounced and, occasionally differing, direction of Prins’ results may be attributable to the trial being only quasi-randomized, resulting in no concealment of treatment allocation or blinding. In order to test the robustness of the results, the authors of this review performed several sensitivity analyses both with and without Prins’ trial data. Excluding this trial reduced the variability of results between trials, and eliminated all significant benefits in applicable primary outcomes for surgical intervention. When interpreting the results, it is also important to explicitly recognize characteristics of patients enrolled in the included trials. Both adults with chronic ankle instability and children were deliberately excluded. The majority of patients in these trials were young active adult males suffering from ankle injuries that were painful and/or swollen enough for them to present to an acute care setting. In other words, these are patients who had relatively severe injuries, and theoretically are most likely to have benefited from surgical intervention. In general, one would expect a patient presenting to an ambulatory or primary care clinic to have an even more diminished benefit from surgical intervention. This is an important consideration when determining the clinical relevance of the results. Take-Home Messages Overall, this Cochrane Review (which is current to January 2006) failed to demonstrate a benefit of surgery compared with conservative management for acute lateral ligament complex injuries. Since this review was conducted, at least two more randomized controlled trials have been published comparing conservative and surgical management for acute lateral ligament complex injuries [8, 11]. Both of these trials failed to demonstrate significant differences between surgery and conservative management in their primary outcomes, further corroborating the findings of this Cochrane review. Because studies have failed to consistently demonstrate evidence of benefit for surgical repair, along with the additional complications inherent with an invasive surgical procedure, surgery for acute lateral ligament complex injuries is not recommended, regardless of severity. The optimal method of conservative management (rigid immobilization versus early mobilization) remains a topic of ongoing investigation. The development of a standardized outcome instrument that is validated, reliable, and universally accepted will facilitate analysis of future trials in foot and ankle surgery.